Methods and apparatus for implementing quality-of-service guarantees in data storage systems

摘要

The value of a p-quantile of a workload distribution is computed to determine whether a data storage system satisfies a quality- of- service guarantee desired by a client. The quality-of-service guarantee may be a predetermined percentage of a workload being serviced by a device within a predetermined response time. A p-quantile value is set to be equal of the predetermined percentage of the quality-of-service guarantee, and a bound is set to be equal to the predetermined response time. A distribution for the workload arriving at the device during an interval of time equal to the bound is then estimated. It is then determined whether a p-quantile of the workload distribution is less than the bound. In cases where the p-quantile of the workload distribution is computed directly, then the p-quantile of the workload distribution is directly compared to the bound. In cases where the p- quantile of the workload distribution is not computed directly, then the p-quantile of the workload distribution is estimated, with the estimated value the compared to the bound.